An enterprise network's effectiveness is directly impacted by whether or not a dial plan meets or fails to meet a company's requirements. It is the responsibility of an enterprise network administrator to ensure that the network has been set up to handle telephone calls in an efficient way. A telephone numbering plan is a set of rules used to assign telephone numbers and features to users and to route calls within telephone networks. The dial plan is a specific set of country codes, area codes, access codes, or combinations of dialed digits that sets the number and patterns of digits for all calls and administered features in the network. The typical dial plan models include open and closed dial plans, where an open dial plan allows variability of length of dialed digits and closed dial plan has a fixed total length of dialed digits.
Administrators typically build dial patterns/plans that are location-specific. The dial patterns often include “short codes” for dialing people that are collocated, and the short codes may not be unique across the enterprise network in different locations. Each location typically has local dialing rules such as “9” to get an outside line, “1” for long distance, and “011” for international in the United States.
Historically, dial plans have included some or all of the following routing tables/strategies in addition to short codes and local dialing rules: Automated Alternate Routing (AAR—private), Automatic Route Selection (ARS—public), Uniform Dial Plan (UDP—other, not AAR or ARS), and Feature Access Codes (FAC). There is no uniform graphic depiction of routing, and the tables listed above are commonly in text data entry format only.
With the complexity of today's private branch exchanges (PBXs), diversity of locations and distributed models, and the use of multiple protocols in hybrid networks (e.g., VoIP, SIP, Virtual), establishing and managing an effective dial plan has become increasingly challenging. A question arises as to how the dial plan in an enterprise network can be easily and effectively managed and displayed.